Positive electrode for all-solid-state battery, all-solid-state battery including same, and method of manufacturing same

Abstract

The invention discloses a positive electrode, an all-solid-state battery and a manufacturing method of the positive electrode. The positive electrode includes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector. The positive electrode active material layer includes: a sulfide-based solid electrolyte; the binding agent comprises a first non-aqueous binding agent and a second non-aqueous binding agent; and a positive electrode active material. The first non-aqueous binder includes a fluorine-based binder. And the second non-aqueous binder comprises an acrylic ester binder.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2024-0124427, filed on September 12, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure relates to a positive electrode for an all-solid-state battery, an all-solid-state battery including the positive electrode, and a method for manufacturing the positive electrode. More specifically, it relates to a positive electrode including two or more non-aqueous binders, an all-solid-state battery including the positive electrode, and a method for manufacturing the positive electrode. Background Technology

[0003] The demand for high-energy-density and safe batteries driven by industrial needs is increasing. For example, lithium-ion batteries are being commercialized not only in formation-related and communication devices, but also in the automotive industry. In the automotive industry, safety is emphasized due to its direct relationship with human safety.

[0004] Some all-solid-state batteries use a solid electrolyte instead of a liquid electrolyte. Because all-solid-state batteries do not use flammable organic dispersion media, the likelihood of fire or explosion is significantly reduced, even in the event of a short circuit. Therefore, such all-solid-state batteries can exhibit increased safety compared to lithium-ion batteries that use liquid electrolytes. Summary of the Invention

[0005] Example embodiments of this disclosure include a positive electrode for an all-solid-state battery that has increased adhesion between the positive electrode current collector and the positive electrode active material layer.

[0006] Example embodiments of this disclosure include all-solid-state batteries that include the positive electrode and have improved stability and electrochemical properties.

[0007] According to an example embodiment of this disclosure, the positive electrode for an all-solid-state battery may include: a positive electrode current collector; and a positive electrode active material layer on the positive electrode current collector. The positive electrode active material layer may include: a sulfide-based solid electrolyte; a binder, including a first non-aqueous binder and a second non-aqueous binder; and the positive electrode active material. The first non-aqueous binder may include a fluorinated binder. The second non-aqueous binder may include an acrylate binder.

[0008] According to an example embodiment of this disclosure, a method for manufacturing a positive electrode for an all-solid-state battery may include the steps of: preparing a slurry; and coating the slurry onto a positive electrode current collector to form a positive electrode active material layer. The step of preparing the slurry may include mixing the positive electrode active material, a sulfide-based solid electrolyte, and a binder in a nonpolar solvent. The binder may include: a first non-aqueous binder, including a fluorinated binder; and a second non-aqueous binder, including an acrylate binder.

[0009] According to exemplary embodiments of this disclosure, an all-solid-state battery may include: a positive electrode layer and a negative electrode layer, opposite to each other; and a solid electrolyte layer, between the positive electrode layer and the negative electrode layer. The positive electrode layer may include a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector. The positive electrode active material layer may include a positive electrode active material, a binder, and a sulfide-based solid electrolyte. The binder may include: a first non-aqueous binder, including a fluorinated binder; and a second non-aqueous binder, including an acrylate binder. Attached Figure Description

[0010] Figure 1 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0011] Figure 2 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0012] Figure 3 and Figure 4 Plan view and cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure are shown respectively.

[0013] Figure 5 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0014] Figure 6 A cross-sectional view is shown illustrating an all-solid-state battery including a gasket structure according to an example embodiment of the present disclosure.

[0015] Figure 7 It shows Figure 1 A magnified view of part M.

[0016] Figure 8 A conceptual diagram illustrating a method for manufacturing a positive electrode for an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0017] Figure 9 A conceptual diagram illustrating a slitting process according to an example embodiment of the present disclosure is shown.

[0018] Figure 10A graph showing the measurement results of the lifetime evaluation of the embodiment and Comparative Example 3 is presented.

[0019] Figure 11 A graph showing the measurement results of the lifetime evaluation of the embodiment and Comparative Example 4 is presented.

[0020] Figure 12 This is a flowchart illustrating a method for manufacturing a positive electrode for an all-solid-state battery according to an example embodiment. Detailed Implementation

[0021] To fully understand the structure and effects of this disclosure, some exemplary embodiments of the disclosure have been described with reference to the accompanying drawings. However, it should be noted that this disclosure is not limited to the following exemplary embodiments, but can be implemented in various forms. Rather, the exemplary embodiments are provided merely to disclose the disclosure and to enable those skilled in the art to fully understand its scope.

[0022] In this specification, it is understood that when an element is referred to as being "on" another element, the element may be "directly on" said other element, or an intervening element may be present between them. In the accompanying drawings, the thickness of some components is exaggerated for the purpose of effectively explaining the technical content. Throughout the specification, the same reference numerals refer to the same elements.

[0023] Some exemplary embodiments described in detail herein are discussed with reference to sectional views and / or plan views, which serve as ideal example views of this disclosure. In the drawings, the thickness of layers and regions may be exaggerated for the purpose of effectively explaining the technical content. Therefore, the regions shown as examples in the drawings have general characteristics, and the shapes of the regions shown as examples in the drawings are used to disclose specific shapes but do not limit the scope of this disclosure. It is understood that although the terms "first," "second," "third," etc., may be used herein to describe various elements, these elements may not be limited by these terms. These terms are used only to distinguish one element from another. The exemplary embodiments explained and illustrated herein include complementary embodiments thereof.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular form is also intended to include the plural form. The term "comprising / including" and / or variations thereof as used in the specification does not exclude the presence or addition of one or more other components.

[0025] In this specification, the term "combination thereof" may refer to mixtures, stacks, complexes, copolymers, alloys, blends, or reaction products.

[0026] Unless otherwise defined in this specification, particle size may refer to the average particle size. Additionally, particle size refers to the average particle size (D) of particles that constitute approximately 50% by volume of the cumulative volume in the particle size distribution.50 Average particle size (D) 50 The particle size can be measured using methods known to those skilled in the art, such as by a particle size analyzer, transmission electron microscopy (TEM) images, or scanning electron microscopy (SEM) images. Alternatively, data analysis can be performed using a dynamic light scattering measurement device to count the number of particles in each particle size range, from which the average particle size (D) can be calculated. 50 The average particle size (D) can be measured using laser scattering, unlike other methods. 50 In the laser scattering method, target particles are distributed in a dispersion solvent and introduced into a laser scattering particle measuring device (e.g., the MT3000 commercially available from Microtrac). They are irradiated with 28 kHz ultrasound at a power of 60 W, and then the average particle size (D) is calculated in the measuring device using a 50% standard of particle size distribution. 50 ).

[0027] When the terms “about” or “substantially” are used in conjunction with numerical values ​​in this specification, it is intended that the relevant numerical values ​​include a tolerance of ±10% around the stated value. When a range is specified, the range includes all values ​​within that range, such as increments of 0.1%.

[0028] Figure 1 A cross-sectional view is shown, illustrating an all-solid-state battery 10 according to an example embodiment of the present disclosure.

[0029] Reference Figure 1 The all-solid-state battery 10 according to an example embodiment may include a positive electrode layer 100, a negative electrode layer 200 opposite to the positive electrode layer 100, and a solid electrolyte layer 300 between the positive electrode layer 100 and the negative electrode layer 200. However, this disclosure is not limited thereto, and the all-solid-state battery 10 may also include additional functional layers, such as an adhesion-enhancing layer, disposed between the positive electrode layer 100 and the solid electrolyte layer 300 or between the negative electrode layer 200 and the solid electrolyte layer 300.

[0030] The positive electrode layer 100 of the exemplary embodiment may include a positive electrode current collector 110 and a positive electrode active material layer 120 disposed on the positive electrode current collector 110. The positive electrode active material layer 120 may include a positive electrode active material, a solid electrolyte, a conductive material, and a binder.

[0031] The positive electrode current collector 110 can provide a reference surface on which the positive electrode active material layer 120 is disposed. The positive electrode current collector 110 may include a plate or foil, which includes at least one of, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), and alloys thereof.

[0032] and Figure 1 The construction shown is different; in the example embodiment of this disclosure, the positive electrode current collector 110 may be omitted. Although not shown, in order to increase the adhesion between the positive electrode current collector 110 and the positive electrode active material layer 120, a carbon layer with a thickness of about 0.1 μm to about 4 μm may be further provided between the positive electrode current collector 110 and the positive electrode active material layer 120.

[0033] The positive electrode active material layer 120 may include a positive electrode active material, a solid electrolyte, a conductive material, and a binder.

[0034] The positive electrode active material may include materials capable of reversibly inserting and deintercalating lithium ions. The positive electrode active material may include, for example, at least one of lithium transition metal oxides (e.g., lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganese oxide, or lithium iron phosphate), nickel sulfide, copper sulfide, lithium sulfide, iron oxide, and vanadium oxide, but this disclosure is not limited thereto. The positive electrode active material may be included alone or as a mixture of two or more substances.

[0035] Lithium transition metal oxides can be or include, for example, compounds represented by one of the following: Li a A 1-b B b D2 (where 0.90≤a≤1 and 0≤b≤0.5); Li a E 1-b B b O 2-c D c (Where, 0.90≤a≤1, 0≤b≤0.5, and 0≤c≤0.05); LiE 2-b B b O 4-c D c (Where, 0 ≤ b ≤ 0.5, and 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B c D α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α<2); Li a Ni 1-b-c Co b B c O 2-α F α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α<2); Li a Ni1-b-c Mn b B c D α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α≤2); Li a Ni 1-b-c Mn b B c O 2-α F α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α<2); Li a Ni b E c G d O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, and 0.001≤d≤0.1); Li a Ni b Co c Mn d G e O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, and 0.001≤e≤0.1); Li a NiG b O2 (where 0.9 ≤ a ≤ 1, and 0.001 ≤ b ≤ 0.1); Li a CoG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1); Li a MnG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1); Li a Mn2G b O4 (where 0.90≤a≤1 and 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiIO2; LiNiVO4; Li 3-f J2(PO4)3 (where 0≤f≤2); Li 3-fFe2(PO4)3 (where 0 ≤ f ≤ 2); LiFePO4. Among the above compounds, "A" can be or include at least one of Ni, Co, Mn, and combinations thereof, "B" can be or include at least one of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, and combinations thereof, "D" can be or include at least one of O, F, S, P, and combinations thereof, "E" can be or include at least one of Co, Mn, and combinations thereof, "F" can be or include at least one of F, S, P, and combinations thereof, "G" can be or include at least one of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and combinations thereof, "Q" can be or include at least one of Ti, Mo, Mn, and combinations thereof, "I" can be or include at least one of Cr, V, Fe, Sc, Y, and combinations thereof, and "J" can be or include at least one of V, Cr, Mn, Co, Ni, Cu, and combinations thereof.

[0036] The positive electrode active material can include, for example, a lithium salt of a transition metal oxide having a layered rock salt-type structure among the lithium transition metal oxides discussed above. The term "layered rock salt-type structure" can refer to a structure in which oxygen atom layers and metal atom layers are alternately and regularly arranged in the <111> direction of the cubic rock salt-type structure, where each atom layer forms a two-dimensional plane. The term "cubic rock salt-type structure" can refer to a sodium chloride (NaCl)-type structure as a type of crystal structure, for example, having a face-centered cubic lattice (FCC) formed or including cations and anions arranged such that the edges of the unit lattice are shifted by 1 / 2 of each other. The lithium transition metal oxide having a layered rock salt-type structure can be or include a ternary lithium transition metal oxide, such as LiNi x Co y Al z O2 (NCA) or LiNi x Co y Mn z O2 (NCM) (where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1). When the positive electrode active material includes a ternary lithium transition metal oxide having a layered rock salt-type structure, the all-solid-state battery 10 can improve the energy density and thermal stability.

[0037] The compound included in the positive electrode active material may be coated (not shown). The positive electrode active material may be included as a mixture of the compound and the compound to which the coating is added. The coating added to the surface of the positive electrode active material may include at least one of oxides, hydroxides, hydroxyoxides, oxycarbonates, and bicarbonates of the coating element, as discussed below. The compound forming the coating may be amorphous or crystalline. The coating element included in the coating may include at least one of Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, and mixtures thereof. The coating may include, for example, Li₂O-ZrO₂ (LZO). The method of forming the coating may be any method that does not adversely affect the physical properties of the positive electrode active material. For example, spraying or dipping may be used to form the coating.

[0038] When the positive electrode active material is a ternary lithium transition metal oxide (such as NCA or NCM) including nickel (Ni), the capacity density of the all-solid-state battery 10 can be increased to reduce metal leaching of the positive electrode active material under charging conditions. Therefore, the all-solid-state battery 10 can improve its cycle characteristics under charging conditions. The term "cycle characteristics" can refer to the properties that indicate the degree of degradation of the all-solid-state battery 10 due to charging and discharging. For example, an all-solid-state battery 10 with high cycle characteristics may degrade less due to charging and discharging, while an all-solid-state battery 10 with low cycle characteristics may degrade more due to charging and discharging.

[0039] The positive electrode active material can have a particle shape, for example, approximately spherical or approximately elliptical. There are no restrictions on the particle size and amount of the positive electrode active material.

[0040] Solid electrolytes can have a particulate shape. Solid electrolytes can be dispersed between positive electrode active materials. Solid electrolytes can include sulfide-based solid electrolytes with desired or improved lithium-ion conductivity. Sulfide-based solid electrolytes can include at least one of the following, for example: Li₂S-P₂S₅; Li₂S-P₂S₅-LiX (where X is a halogen element); Li₂S-P₂S₅-Li₂O; Li₂S-P₂S₅-Li₂O-LiI; Li₂S-SiS₂; Li₂S-SiS₂-LiI; Li₂S-SiS₂-LiBr; Li₂S-SiS₂-LiCl; Li₂S-SiS₂-B₂S₃-LiI; Li₂S-SiS₂-P₂S₅-LiI; Li₂S-B₂S₃; Li₂S-P₂S₅-Z m S n (Where m and n are both positive integers, and "Z" is or includes at least one of Ge, Zn, and Ga); Li2S-GeS2; Li2S-SiS2-Li3PO4; Li2S-SiS2-Lip MO q (Where p and q are both positive integers, and "M" is or includes at least one of P, Si, Ge, B, Al, Ga, and In); Li 7-x PS 6-x Cl x (where 0 ≤ x ≤ 2); Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2); and Li 7-x PS 6-x I x (where 0 ≤ x ≤ 2).

[0041] Sulfide solid electrolytes may be or include silver-germanium sulfide compounds, such as Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2) and Li 7-x PS 6-x I x (where 0 ≤ x ≤ 2) at least one of the following. For example, sulfide solid electrolytes may be or include argillaceous sulfide compounds, which include at least one of Li6PS5Cl, Li6PS5Br and Li6PS5I.

[0042] Optionally, the sulfide solid electrolyte may be or include silver-germanium sulfide compounds, including Li 7-a M a PS 6-c X c (Where 0 ≤ a ≤ 2 and 0 ≤ c ≤ 2). In the above chemical formulas, X can be or includes at least one of F, Br, Cl, I, and combinations thereof. Additionally, M can be or includes at least one of scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), and combinations thereof.

[0043] In contrast, the sulfide-based solid electrolyte can be the same as the solid electrolyte included in the solid electrolyte layer 300 discussed below.

[0044] The argyrogermanium sulfide solid electrolyte can have a density in the range of about 1.5 g / cc to about 2.0 g / cc. Since the density of the argyrogermanium sulfide solid electrolyte is equal to or greater than about 1.5 g / cc, it is possible to reduce the internal resistance of the all-solid-state battery and reduce or prevent short circuits and penetration of the solid electrolyte layer due to lithium dendrite formation. The solid electrolyte can have an elastic modulus in the range of, for example, about 15 GPa to about 35 GPa.

[0045] The solid electrolyte included in the positive electrode active material layer 120 can have an average particle size (D) smaller than the average particle size of the solid electrolyte included in the solid electrolyte layer 300. 50 For example, the average particle size (D) of the solid electrolyte in the positive electrode active material layer 120 is of moderate size. 50 The average particle size (D) of the solid electrolyte included in the solid electrolyte layer 300 can be equal to or smaller than the average particle size of the solid electrolyte. 50 Approximately 90%, 80%, 70%, 60%, 50%, 40%, 30%, or 20% of the average particle size (D) of medium-sized particles. 50 The median diameter can be measured using a laser particle size distribution analyzer.

[0046] The positive electrode active material layer 120 may include a conductive material. The conductive material may be conductive without causing chemical changes in the all-solid-state battery 10, thereby increasing the conductivity of the positive electrode active material and the solid electrolyte.

[0047] Conductive materials can include carbon-based materials. Conductive materials can include one or more of, for example, graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0048] The positive electrode active material layer 120 may further include an adhesive. The adhesive may include a material that adheres the positive electrode active material, solid electrolyte, and conductive material included in the positive electrode active material layer 120 together and improves the adhesion between the positive electrode active material layer 120 and the positive electrode current collector 110. The adhesive may include one or more of, for example, polyvinylidene fluoride, styrene-butadiene rubber (SBR), polytetrafluoroethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0049] Based on a total of 100 parts by weight of the positive electrode active material, solid electrolyte, conductive material, and binder, the positive electrode active material may be included in the positive electrode active material layer 120 in an amount ranging from about 85 parts by weight to about 92 parts by weight. Based on a total of 100 parts by weight of the positive electrode active material, solid electrolyte, conductive material, and binder, the conductive material may be included in the positive electrode active material layer 120 in an amount ranging from about 0.5 parts by weight to about 1.5 parts by weight.

[0050] Based on 100 parts by weight of solid electrolyte, conductive material may be included in the positive electrode active material layer 120 in an amount ranging from about 1 part by weight to about 50 parts by weight. When the positive electrode active material layer 120 includes conductive material in an amount of less than about 1 part by weight based on 100 parts by weight of solid electrolyte, the proportion of conductive material may decrease, thereby reducing the conductivity of the positive electrode active material layer 120. When the positive electrode active material layer 120 includes conductive material in an amount of greater than about 50 parts by weight based on 100 parts by weight of solid electrolyte, the proportion of conductive material may increase significantly, resulting in incomplete formation of the coating covering the surface of the solid electrolyte.

[0051] In addition to the positive electrode active material, solid electrolyte, conductive material and binder, the positive electrode active material layer 120 may also include additives such as fillers, coating agents, dispersants and ionic conductive agents.

[0052] Reference Figure 1 The negative electrode layer 200 may include a negative electrode current collector 210 and a negative electrode active material layer 220 on the negative electrode current collector 210. The negative electrode active material layer 220 may include a negative electrode active material and a binder.

[0053] The negative electrode current collector 210 can provide a reference surface on which the negative electrode active material layer 220 is disposed. The negative electrode current collector 210 may include materials that do not react with lithium or substantially do not react with lithium, such as materials that do not form alloys or compounds with lithium. For example, the negative electrode current collector 210 may include or contain at least one metallic material selected from copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni), but this disclosure is not limited thereto and may include any material suitable for the electrode current collector. The thickness of the negative electrode current collector 210 may range from about 1 μm to about 20 μm, for example, from about 5 μm to about 15 μm or from about 7 μm to about 10 μm.

[0054] The negative electrode current collector 210 may be formed of one of the aforementioned metals, an alloy of two or more of the aforementioned metals, or a coating material, or may include one of the aforementioned metals, an alloy of two or more of the aforementioned metals, or a coating material. The negative electrode current collector 210 may have, for example, a plate or foil shape. In the example embodiment, the negative electrode current collector 210 may be omitted.

[0055] The negative electrode active material included in the negative electrode active material layer 220 can have a particulate shape. The particulate negative electrode active material can have an average particle size (D) in the range of, for example, equal to or less than about 4 μm, equal to or less than about 2 μm, equal to or less than about 1 μm, or equal to or less than about 900 nm. 50 The average particle size (D) of the medium-sized active material of the negative electrode 50 The particle size can be, for example, in the range of about 10 nm to about 4 μm, about 10 nm to about 2 μm, or about 10 nm to about 900 nm. This is because the negative electrode active material has an average particle size (D) falling within the above range. 50 Therefore, lithium insertion and / or extraction can be more easily achieved during charging and discharging. The average particle size (D) is of medium size. 50 The median diameter can be measured using a laser particle size distribution analyzer.

[0056] The negative electrode active material may include one or more of, for example, carbon-based negative electrode active materials, metal negative electrode active materials, and quasi-metal negative electrode active materials.

[0057] The active material for a carbon-based negative electrode can be amorphous carbon. Amorphous carbon can be or include at least one of, for example, carbon black (CB), acetylene black (AB), furnace black (FB), Ketjen black (KB), and graphene, but this disclosure is not limited thereto. Amorphous carbon can be or includes carbon lacking crystallinity or having a relatively low degree of crystallinity, and can be distinguished from crystalline carbon or graphitic carbon.

[0058] Metallic negative electrode active materials or quasi-metallic negative electrode active materials may include one or more of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn), but this disclosure is not limited thereto, and may be or include metallic negative electrode active materials or quasi-metallic negative electrode active materials that form alloys or compounds with lithium. Since nickel (Ni) does not form alloys with lithium, nickel (Ni) cannot be classified as a metal in metallic negative electrode active materials.

[0059] The negative electrode active material layer 220 may include one of the above-mentioned materials or a mixture of different materials. For example, the negative electrode active material layer 220 may include only amorphous carbon, or one or more of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).

[0060] In an exemplary embodiment, the negative electrode active material layer 220 may comprise a mixture of amorphous carbon and at least one of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). In the mixture of amorphous carbon and a material such as or including gold (Au), the amorphous carbon and said material may be mixed in a weight ratio ranging from, for example, about 10:1 to about 1:2, about 5:1 to about 1:1, or about 4:1 to about 2:1, but this disclosure is not limited thereto, and said weight ratio may be selected based on the desired properties of the all-solid-state battery 10. When the negative electrode active material has such a composition, the cycle characteristics of the all-solid-state battery 10 can be improved.

[0061] The binder included in the negative electrode active material layer 220 may include at least one of, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate, but this disclosure is not limited thereto. The binder may be configured as a single binder or a variety of different binders.

[0062] Because the negative electrode active material layer 220 includes a binder, it can be stably formed on the negative electrode current collector 210. For example, increased adhesion can be observed between the negative electrode active material layer 220 and the negative electrode current collector 210. Furthermore, although the volume and / or relative position of the negative electrode active material layer 220 changes during charging and discharging, the occurrence of cracks in the negative electrode active material layer 220 can be reduced or suppressed. When the negative electrode active material layer 220 does not include a binder, it can be easily separated from the negative electrode current collector 210. Because the negative electrode active material layer 220 is separated from the negative electrode current collector 210, the negative electrode current collector 210 may come into contact with the solid electrolyte layer 300 in the exposed area, potentially increasing the likelihood of a short circuit.

[0063] The negative electrode active material layer 220 can be manufactured, for example, by providing a mixture of materials in which the negative electrode active material layer 220 is dispersed on the negative electrode current collector 210. Since the binder is included in the material of the negative electrode active material layer 220, it is possible to stably disperse the negative electrode active material in the mixture. For example, when the mixture is screen-printed onto the negative electrode current collector 210, it is possible to reduce or suppress screen clogging caused by the binder (e.g., clogging caused by aggregates of the negative electrode active material).

[0064] In addition to the negative electrode active material and binder, the negative electrode active material layer 220 may also include various additives. For example, the negative electrode active material layer 220 may also include fillers, coating agents, dispersants, ionic conductive agents, etc.

[0065] The negative electrode active material layer 220 can have a thickness smaller than that of the positive electrode active material layer 120. For example, the thickness of the negative electrode active material layer 220 can be equal to or less than about 50%, about 40%, about 30%, about 20%, about 10%, or about 5% of the thickness of the positive electrode active material layer 120. The thickness of the negative electrode active material layer 220 can be in the range of, for example, about 1 μm to about 20 μm, about 2 μm to about 10 μm, or about 3 μm to about 7 μm. When the negative electrode active material layer 220 has a relatively small thickness (e.g., less than about 1 μm), lithium dendrites formed between the negative electrode active material layer 220 and the negative electrode current collector 210 may cause the negative electrode active material layer 220 to collapse, thereby reducing the cycle characteristics of the all-solid-state battery 10. When the negative electrode active material layer 220 has a considerable thickness (e.g., greater than about 20 μm), the all-solid-state battery 10 may have a reduced energy density, and the internal resistance of the all-solid-state battery 10 may increase due to the negative electrode active material layer 220, thereby reducing the cycle characteristics of the all-solid-state battery 10.

[0066] A reduction in the thickness of the negative electrode active material layer 220 may, for example, lead to a decrease in the charging capacity of the negative electrode active material layer 220. The charging capacity of the negative electrode active material layer 220 may be equal to or less than approximately 50%, approximately 40%, approximately 30%, approximately 20%, approximately 10%, approximately 5%, or approximately 2% of the charging capacity of the positive electrode active material layer 120. The charging capacity of the negative electrode active material layer 220 may be approximately 0.1% to approximately 50%, approximately 0.1% to approximately 40%, approximately 0.1% to approximately 30%, approximately 0.1% to approximately 20%, approximately 0.1% to approximately 10%, or approximately 0.1% to approximately 2% of the charging capacity of the positive electrode active material layer 120. When the negative electrode active material layer 220 has a considerably small charging capacity, the negative electrode active material layer 220 may have a considerably small thickness, and when the thickness of the negative electrode active material layer 220 is considerably small, as described above, a malfunction may occur. The significant increase in the thickness of the negative electrode active material layer 220 may lead to a malfunction due to the significant increase in its charging capacity.

[0067] For example, the charging capacity of the positive electrode active material layer 120 can be obtained by multiplying the charging capacity density (mAh / g) of the positive electrode active material by the mass of the positive electrode active material in the positive electrode active material layer 120. When the positive electrode active material layer 120 includes various positive electrode active materials, the value of [charging capacity density × mass] for each positive electrode active material can be calculated, and the sum of these values ​​for the positive electrode active materials can be the charging capacity of the positive electrode active material layer 120. The charging capacity of the negative electrode active material layer 220 can also be calculated in the same way. For example, the charging capacity of the negative electrode active material layer 220 can be obtained by multiplying the charging capacity density (mAh / g) of the negative electrode active material by the mass of the negative electrode active material in the negative electrode active material layer 220. When the negative electrode active material layer 220 includes various negative electrode active materials, the value of [charging capacity density × mass] for each negative electrode active material can be calculated, and the sum of these values ​​for the negative electrode active materials can be the charging capacity of the negative electrode active material layer 220. Here, the charge capacity density of each of the positive and negative electrode active materials can be an estimated capacity using an all-solid-state half-cell, which includes lithium metal as the counter electrode. The charge capacity of each of the positive electrode active material layer 120 and the negative electrode active material layer 220 can be directly measured using charge capacity measurements of an all-solid-state half-cell. The charge capacity density can be obtained by dividing the measured charge capacity by the mass of each active material. In this specification, the term "charge capacity" for each of the positive electrode active material layer 120 and the negative electrode active material layer 220 can refer to the initial charge capacity measured during the first charge cycle.

[0068] Although not shown, a carbon layer may be further included to increase the adhesion between the negative electrode active material layer 220 and the solid electrolyte layer 300.

[0069] A solid electrolyte layer 300 may be disposed between the positive electrode layer 100 and the negative electrode layer 200. The solid electrolyte layer 300 may include a sulfide-based solid electrolyte having a desired or improved lithium-ion conductivity. The solid electrolyte layer 300 may include a solid electrolyte, which may be the same as or different from the solid electrolyte of the positive electrode active material layer 120.

[0070] In an example embodiment, the solid electrolyte included in the solid electrolyte layer 300 may be in an amorphous, crystalline, or mixed state of amorphous and crystalline states. The solid electrolyte may include at least one of the constituent elements of sulfur (S), phosphorus (P), and lithium (Li) included in the aforementioned sulfide-based solid electrolytes. For example, the solid electrolyte may be or include a material comprising Li₂S-P₂S₅. When a material comprising Li₂S-P₂S₅ is used as the sulfide-based solid electrolyte material, the molar ratio of Li₂S to P₂S₅ may be in the range of approximately 50:50 to approximately 90:10.

[0071] Sulfide solid electrolytes may be or include silver-germanium sulfide compounds, such as Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2) and Li 7-x PS 6-x I x (where 0 ≤ x ≤ 2) at least one of the following. For example, sulfide solid electrolytes may be or include argillaceous sulfide compounds, which include at least one of Li6PS5Cl, Li6PS5Br and Li6PS5I.

[0072] Optionally, the sulfide solid electrolyte may be or include silver-germanium sulfide compounds, including Li 7-a M a PS 6-c X c(Where 0≤a≤2 and 0≤c≤2). In the above chemical formulas, X can be at least one of F, Br, Cl, I, and combinations thereof. M can be or include at least one of scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), and combinations thereof.

[0073] The argyrogermanium sulfide solid electrolyte can have a density in the range of about 1.5 g / cc to about 2.0 g / cc. Since the density of the argyrogermanium sulfide solid electrolyte is equal to or greater than about 1.5 g / cc, it is possible to reduce the internal resistance of the all-solid-state battery and prevent or inhibit short circuits and penetration of the solid electrolyte layer due to lithium dendrite formation. The solid electrolyte can have an elastic modulus in the range of, for example, about 15 GPa to about 35 GPa.

[0074] The solid electrolyte layer 300 may further include an adhesive. The adhesive included in the solid electrolyte layer 300 may include at least one of styrene-butadiene rubber (SBR), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and polyethylene, but this disclosure is not limited thereto. For example, the adhesive may include at least one of styrene-butadiene rubber, PTFE, PVDF, polyethylene, polyvinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, and isobutyl isobutyrate. The adhesive of the solid electrolyte layer 300 may be the same as or different from the adhesive of the positive electrode active material layer 120 or the adhesive of the negative electrode active material layer 220.

[0075] Figure 2 A cross-sectional view is shown, illustrating an all-solid-state battery 10 according to an example embodiment of the present disclosure.

[0076] Reference Figure 2 The solid electrolyte layer 300 may include a first solid electrolyte layer 310 and a second solid electrolyte layer 320. The first solid electrolyte layer 310 may be adjacent to the positive electrode layer 100, and the second solid electrolyte layer 320 may be adjacent to the negative electrode layer 200.

[0077] The first solid electrolyte layer 310 and the second solid electrolyte layer 320 may have different thicknesses. The first solid electrolyte layer 310 may have a first thickness TK1, and the second solid electrolyte layer 320 may have a second thickness TK2. The first thickness TK1 may be greater than the second thickness TK2. For example, the first thickness TK1 may be about 2 to about 100 times the second thickness TK2.

[0078] Figure 3 A plan view of an all-solid-state battery 10 according to an example embodiment of the present disclosure is shown. Figure 4 It shows along Figure 3 The sectional view taken along line A-A'. In the following description, references to the above are omitted. Figure 1 and Figure 2 The technical features discussed are repeated in detail, and their differences are discussed in detail.

[0079] Reference Figure 3 and Figure 4 The areas of the positive electrode layer 100 and the negative electrode layer 200 can be different from each other. For example, the area of ​​the negative electrode layer 200 can be larger than the area of ​​the positive electrode layer 100. The positive electrode layer 100 can be stacked vertically with the negative electrode layer 200. The positive electrode layer 100 can be completely stacked inward with the negative electrode layer 200.

[0080] In an exemplary embodiment of this disclosure, the first solid electrolyte layer 310 may have an area substantially the same as that of the positive electrode layer 100. The second solid electrolyte layer 320 may have an area substantially the same as that of the negative electrode layer 200.

[0081] The first solid electrolyte layer 310 may have a first width WI1 in the first direction D1. The second solid electrolyte layer 320 may have a second width WI2 in the first direction D1. The first width WI1 may be smaller than the second width WI2. The first solid electrolyte layer 310 may have a third width WI3 in the second direction D2. The second solid electrolyte layer 320 may have a fourth width WI4 in the second direction D2. The third width WI3 may be smaller than the fourth width WI4.

[0082] The all-solid-state battery 10 according to the example embodiment can be manufactured by forming a first stack of a positive electrode layer 100 and a first solid electrolyte layer 310, forming a second stack of a negative electrode layer 200 and a second solid electrolyte layer 320, and then laminating the first stack and the second stack.

[0083] Figure 5 The diagram illustrates an all-solid-state battery according to an example embodiment of the present disclosure. Figure 3 A sectional view taken by line A-A'.

[0084] Reference Figure 5 The negative electrode layer 200 of the all-solid-state battery 10 may further include a lithium metal layer 400 between the negative electrode current collector 210 and the negative electrode active material layer 220. When the all-solid-state battery 10 is charged, the lithium metal layer 400 may have an increased thickness. The negative electrode active material layer 220 may be configured as a protective layer for the lithium metal layer 400, and may simultaneously or concurrently reduce or suppress the growth of lithium dendrites from the lithium metal layer 400.

[0085] The lithium metal layer 400 may be or include a thin metal layer comprising lithium or a lithium alloy. The lithium alloy may be or include at least one of, for example, Li-Al alloys, Li-Sn alloys, Li-In alloys, Li-Ag alloys, Li-Au alloys, Li-Zn alloys, Li-Ge alloys, and Li-Si alloys, but may include any suitable lithium alloy. The lithium metal layer 400 may include lithium or one of the aforementioned alloys. Optionally, the lithium metal layer 400 may include various alloys.

[0086] The lithium metal layer 400 may have a fifth width WI5 in the first direction D1. The fifth width WI5 may be the same as or greater than the first width WI1. The fifth width WI5 may be the same as or less than the second width WI2. For example, the fifth width WI5 may be greater than the first width WI1 and less than the second width WI2.

[0087] Figure 6 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0088] Reference Figure 6 The all-solid-state battery 10 may include a gasket structure 500. The area difference between the first and second stacked bodies may create a step difference on the side surface of the all-solid-state battery 10, which the gasket structure 500 can fill. The gasket structure 500 may surround the side surfaces of the first stacked bodies of the all-solid-state battery 10 in a first direction D1 and a second direction D2. For example, the thickness of the gasket structure 500 may be substantially the same as the thickness of the first stacked bodies. Therefore, even when first and second stacked bodies with different areas are stacked and pressed, the all-solid-state battery 10 can be prevented or protected from damage due to step differences on the side surfaces. The expression "substantially the same thickness" can refer to a thickness sufficient to reduce or prevent damage to the all-solid-state battery 10 due to step differences on the side surfaces, even when first and second stacked bodies with different areas are stacked and pressed.

[0089] Figure 7 It shows Figure 1 A magnified view of part of the "M". For the sake of brevity, omissions have been made to avoid confusion with other parts of the text. Figures 1 to 6The description in the discussion is repetitive.

[0090] Reference Figure 7 A positive electrode active material layer 120 can be disposed on the positive electrode current collector 110. The positive electrode active material layer 120 may include the positive electrode active material AM, the sulfide solid electrolyte SE, and the binder BD.

[0091] The binder BD can be present in an amount ranging from about 1 wt% to about 1.5 wt% relative to the 100 wt% positive electrode active material layer 120. When the amount of binder BD falls within the above range, the all-solid-state battery can exhibit the desired or improved stability and electrochemical properties.

[0092] For example, when the amount of binder BD is greater than about 1.5 wt% relative to 100 wt% of the positive electrode active material layer 120, the battery resistance may increase. As a result, the all-solid-state battery may have reduced lifetime efficiency and capacity.

[0093] When the amount of binder BD is less than about 1 wt% relative to 100 wt% of the positive electrode active material layer 120, the low amount of binder BD may lead to a decrease in the stability and adhesion between the positive electrode active material layer 120 and the positive electrode current collector 110.

[0094] The adhesive BD may include a first non-aqueous adhesive BD1 and a second non-aqueous adhesive BD2. The first non-aqueous adhesive BD1 may include a fluorinated adhesive. The fluorinated adhesive may include a polymer derived from a monomer containing fluorine (F). The fluorinated adhesive may include at least one of fluoroalkyl, fluoroalkylene, and perfluoroalkyl groups. The first non-aqueous adhesive BD1 may include at least one of, for example, poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)), poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)), poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-CTFE)), poly(vinylidene fluoride-co-tetrafluoroethylene) (P(VDF-TFE)), and poly(vinylidene fluoride-co-hexafluoropropylene-co-trifluoroethylene) (P(VDF-HFP-TrFE)).

[0095] The second non-aqueous adhesive BD2 may include acrylate adhesives. Acrylate adhesives may include polymers polymerized from monomers containing acrylates (CH2=CHCOO-). The second non-aqueous adhesive BD2 may include at least one of, for example, polyacrylic acid (PAA), polymethyl methacrylate (PMMA), poly(butyl acrylate), poly(ethyl acrylate), and poly(2-ethylhexyl acrylate).

[0096] The amount of the first non-aqueous adhesive BD1 in adhesive BD can be equal to or greater than the amount of the second non-aqueous adhesive BD2 in adhesive BD. The amount of the first non-aqueous adhesive BD1 relative to 100 wt% of adhesive BD can range from about 50 wt% to about 90 wt%. The amount of the second non-aqueous adhesive BD2 relative to 100 wt% of adhesive BD can range from about 10 wt% to about 50 wt%.

[0097] When the amount of each or at least one of the first non-aqueous binder BD1 and the second non-aqueous binder BD2 falls within the above range, the all-solid-state battery can exhibit the desired or improved stability and electrochemical properties.

[0098] For example, when the amount of the first non-aqueous adhesive BD1 is greater than about 90 wt% relative to 100 wt% of the adhesive BD, and when the amount of the second non-aqueous adhesive BD2 is less than about 10 wt% relative to 100 wt% of the adhesive BD, reduced adhesion may be provided between the positive electrode active material layer 120 and the positive electrode current collector 110. When the amount of the first non-aqueous adhesive BD1 is greater than about 90 wt% relative to 100 wt% of the adhesive BD, the positive electrode active material layer 120 may separate from the positive electrode current collector 110 during the slitting process discussed below. Therefore, the failure rate may increase.

[0099] When the amount of the first non-aqueous binder BD1 is less than about 50 wt% relative to 100 wt% binder BD, and when the amount of the second non-aqueous binder BD2 is greater than about 50 wt% relative to 100 wt% binder BD, the viscosity of the slurry comprising the positive electrode active material and the sulfide-based solid electrolyte may increase. This increase in slurry viscosity may lead to uneven mixing of the binder with the positive electrode active material and the sulfide-based solid electrolyte in the slurry. The slurry may be coated substantially unevenly onto the positive electrode current collector 110.

[0100] The adhesion force between the positive electrode active material layer 120 and the positive electrode current collector 110 can range from about 0.5 gf / mm to about 2.5 gf / mm. Adhesion force can refer to the adhesive force when the positive electrode current collector 110 is fixed and the positive electrode active material layer 120 is pulled at an angle of about 180°. Adhesion force can be expressed as adhesive force measured based on the ASTM D903 standard. According to some example embodiments of this disclosure, a positive electrode with desired or improved adhesion force between the positive electrode active material layer 120 and the positive electrode current collector 110 can be provided.

[0101] Figure 8 and Figure 9A diagram illustrating a method for manufacturing a positive electrode for an all-solid-state battery according to an embodiment of the present disclosure is shown. For simplicity, details have been omitted to avoid confusion with... Figures 1 to 7 The description discussed in the text is repeated.

[0102] Reference Figure 8 and Figure 9 The wound positive electrode current collector 110 can be unwound by the supply roller R. The positive electrode current collector 110 can move along the first direction D1.

[0103] A slurry can be prepared. The preparation of the slurry may include mixing a positive electrode active material, a sulfide-based solid electrolyte, and a binder in a nonpolar solvent. The slurry may have a viscosity in the range of about 1,000 mPa·s to about 10,000 mPa·s at room temperature (e.g., about 20°C). Viscosity may refer to, for example, shear viscosity measured using a rheometer commercially available from Anton Paar GmbH. For example, viscosity may be expressed as viscosity at a shear rate of about 10 (1 / s) at room temperature (about 20°C).

[0104] When the viscosity of the slurry falls within the above range, the slurry can be coated substantially uniformly onto the positive electrode current collector 110. For example, when the viscosity is less than about 1,000 mPa·s, the low slurry viscosity may lead to rapid precipitation of the positive electrode active material. Therefore, the variation in the loading level of the electrode plate may increase, and it may be impossible to achieve the desired loading level. The efficiency of the manufacturing process may also decrease. In this specification, the term "loading level" may refer to the amount of active material per unit area of ​​electrode and may be a factor designed by taking into account the diffusion coefficient of lithium ions, conduction between particles, and the path to the current collector.

[0105] When the viscosity of the slurry exceeds approximately 10,000 mPa·s, slurry mixing may become difficult, leading to a decrease in electrochemical properties. Additionally, there may be limitations on slurry supply and reductions in manufacturing processes.

[0106] Nonpolar solvents may include at least one of butyrate, toluene, xylene, anisole, hexane, heptane, dibromomethane, dichloroethane, ethanol, ethylene glycol ether, and combinations thereof.

[0107] Sulfide-based solid electrolytes may react with polar solvents, thus side reactions can occur when polar solvents are included. In methods for manufacturing a positive electrode for an all-solid-state battery according to some example embodiments of this disclosure, non-polar solvents may be included to reduce or prevent the occurrence of side reactions. It may be possible to provide an all-solid-state battery with desired or improved electrochemical properties.

[0108] The binder in the slurry can be present in an amount ranging from about 1 wt% to about 1.5 wt% relative to 100 wt% of the slurry. When the amount of binder falls within the above range, the all-solid-state battery can exhibit the desired or improved stability and electrochemical properties.

[0109] For example, when the amount of binder is greater than about 1.5 wt% relative to 100 wt% of the positive electrode active material layer 120, the increased binder dosage leads to a decrease in ionic conductivity, which may increase the battery resistance. All-solid-state batteries may then exhibit reduced lifetime efficiency and capacity.

[0110] When the amount of binder is less than about 1 wt% relative to 100 wt% of slurry, the stability and adhesion between the positive electrode active material layer 120 and the positive electrode current collector 110 may be reduced.

[0111] The adhesive may include a first non-aqueous adhesive and a second non-aqueous adhesive. The first non-aqueous adhesive may include a fluorinated adhesive. The fluorinated adhesive may include a polymer derived from a monomer containing fluorine (F). The fluorinated adhesive may include at least one of fluoroalkyl, fluoroalkylene, and perfluoroalkyl groups.

[0112] The first non-aqueous adhesive may include at least one of, for example, poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)), poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)), poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-CTFE)), poly(vinylidene fluoride-co-tetrafluoroethylene) (P(VDF-TFE)) and poly(vinylidene fluoride-co-hexafluoropropylene-co-trifluoroethylene) (P(VDF-HFP-TrFE)).

[0113] The second non-aqueous adhesive may include acrylate adhesives. Acrylate adhesives may include polymers polymerized from monomers containing acrylates (CH2=CHCOO-). The second non-aqueous adhesive may include at least one of, for example, polyacrylic acid (PAA), polymethyl methacrylate (PMMA), poly(butyl acrylate), poly(ethyl acrylate), and poly(2-ethylhexyl acrylate).

[0114] The amount of the first non-aqueous binder in the binder can be the same as or different from the amount of the second non-aqueous binder in the binder. The amount of the first non-aqueous binder can range from about 50 wt% to about 90 wt% relative to 100 wt% of the binder. The amount of the second non-aqueous binder can range from about 10 wt% to about 50 wt% relative to 100 wt% of the binder. When the amounts of each of the first and second binders fall within the above ranges, the all-solid-state battery can exhibit desired or improved stability and electrochemical properties.

[0115] For example, when the amount of the first non-aqueous adhesive is greater than about 90 wt% relative to 100 wt% of the adhesive, and when the amount of the second non-aqueous adhesive is less than about 10 wt% relative to 100 wt% of the adhesive, reduced adhesion may be observed between the positive electrode active material layer 120 and the positive electrode current collector 110.

[0116] When the amount of the first non-aqueous binder is less than about 50 wt% relative to 100 wt% of the binder, and when the amount of the second non-aqueous binder is greater than about 50 wt% relative to 100 wt% of the binder, the viscosity of the slurry may increase, resulting in the slurry being unevenly coated on the positive electrode current collector 110, and the positive electrode active material layer 120 being unevenly formed on the positive electrode current collector 110.

[0117] The positive electrode active material, sulfide solid electrolyte, and binder can be referenced above. Figures 1 to 7 The discussion focuses on positive electrode active materials, sulfide solid electrolytes, and binders.

[0118] The slurry supplier SL can supply slurry substantially uniformly onto the positive electrode current collector 110, and the coater CO can coat the slurry onto the positive electrode current collector 110. In the coating process, the slurry can be dried or cured, for example, in the range of about 140°C to about 170°C. The coating process may include pressing the slurry. The coating process can form a positive electrode active material layer 120 on the positive electrode current collector 110. The positive electrode active material layer 120 may correspond to the above-mentioned reference. Figure 6 The positive electrode active material layer 120 is discussed.

[0119] The adhesion force between the positive electrode active material layer 120 and the positive electrode current collector 110 can range from about 0.5 gf / mm to about 2.5 gf / mm. Adhesion force can refer to the adhesive force when the positive electrode current collector 110 is fixed and the positive electrode active material layer 120 is pulled at an angle of about 180°. Adhesion force can be expressed as adhesive force measured based on the ASTM D903 standard. According to some example embodiments of this disclosure, a positive electrode with desired or improved adhesion force between the positive electrode active material layer 120 and the positive electrode current collector 110 can be provided.

[0120] like Figure 9As shown, the positive electrode current collector 110 and the positive electrode active material layer 120 can be stamped by a slitting machine ST. The slitting process can force the positive electrode current collector 110 and the positive electrode active material layer 120 to have substantially the same width. According to some example embodiments of this disclosure, the adhesive may include a first non-aqueous adhesive and a second non-aqueous adhesive, thus providing improved adhesion between the positive electrode current collector 110 and the positive electrode active material layer 120. Although the slitting machine ST applies external force to the positive electrode current collector 110 and the positive electrode active material layer 120, the positive electrode active material layer 120 can be stably placed on the positive electrode current collector 110. The slitting process can reduce or prevent separation of the positive electrode active material layer 120. According to some example embodiments of this disclosure, the method of manufacturing a positive electrode for an all-solid-state battery can provide improved stability and reliability.

[0121] Figure 12 This is a flowchart illustrating a method for manufacturing a positive electrode for an all-solid-state battery according to an example embodiment. Figure 12 In method 1200, the preparation of a slurry includes operation 1210. In one example, preparing the slurry includes mixing a positive electrode active material, a sulfide-based solid electrolyte, and a binder in a nonpolar solvent. For example, the binder includes a first non-aqueous binder and a second non-aqueous binder, the first non-aqueous binder including a fluorinated binder and the second non-aqueous binder including an acrylate binder. In another example, the binder in the positive electrode active material layer is present in an amount ranging from about 1 wt% to about 1.5 wt% relative to 100 wt% of the positive electrode active material layer. For example, the amount of the first non-aqueous binder in the binder is equal to or greater than the amount of the second non-aqueous binder in the binder. In other examples, the first non-aqueous binder in the binder is present in an amount ranging from about 50 wt% to about 90 wt% relative to 100 wt% of the binder, and the second non-aqueous binder in the binder is present in an amount ranging from about 10 wt% to about 50 wt% relative to 100 wt% of the binder.

[0122] In some other examples, the first non-aqueous binder includes at least one of poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)), poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)), poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-CTFE)), poly(vinylidene fluoride-co-tetrafluoroethylene) (P(VDF-TFE)), and poly(vinylidene fluoride-co-hexafluoropropylene-co-trifluoroethylene) (P(VDF-HFP-TrFE)). In some other examples, the non-polar solvent includes at least one of butyrate, toluene, xylene, anisole, hexane, heptane, dibromomethane, dichloroethane, ethanol, ethylene glycol ether, and combinations thereof. For example, the slurry has a viscosity in the range of about 1,000 mPa·s to about 10,000 mPa·s at a temperature of about 20°C. In another example, the adhesion between the positive electrode active material layer and the positive electrode current collector is in the range of about 0.5 gf / mm to about 2.5 gf / mm.

[0123] Operation 1220 includes coating a slurry onto a positive electrode current collector to form a layer of positive electrode active material.

[0124] This disclosure is discussed with reference to example embodiments, examples, and comparative examples.

[0125] Example Prepare 5.0g of LiNi0.8Co0. 15 Mn0. 05 O2 (NCM) powder was used as the positive electrode active material. A crystalline silver-germanium sulfide type solid electrolyte (Li6PS5Cl) was prepared as the solid electrolyte. A binder was prepared in which poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) as the first non-aqueous binder and an acrylic binder (SX-A605, available from Zeon Corporation) as the second non-aqueous binder were mixed. The first non-aqueous binder was present in an amount of 0.9 wt% relative to 100 wt% of the slurry including the positive electrode active material, solid electrolyte, and binder. The second non-aqueous binder was present in an amount of 0.3 wt% relative to 100 wt% of the slurry including the positive electrode active material, solid electrolyte, and binder. Carbon nanofibers (CNF) were prepared as the conductive material. A positive electrode slurry was prepared by mixing the positive electrode active material, solid electrolyte, conductive material, and binder in an octyl acetate solvent at a weight ratio of approximately 85:13.2:0.6:1.2. The positive electrode slurry was then coated onto an aluminum positive electrode current collector and pressed to fabricate the positive electrode.

[0126] Preparation of solid electrolyte layer: Li6PS5Cl, serving as a sulforaphite-germanium ore-type solid electrolyte, was introduced into an isobutyl isobutyrate binder solution containing an acrylate polymer (e.g., polymethyl methacrylate) to prepare a solid electrolyte slurry (the solid electrolyte and binder were mixed at a weight ratio of 98.7:1.3). The prepared solid electrolyte slurry was coated onto a polytetrafluoroethylene release film and dried at 60°C for 2 hours to prepare a solid electrolyte layer with a thickness of 100 μm.

[0127] Manufacturing of the negative electrode: 90wt% silver (Ag) nanoparticles (D 50 A negative electrode coating slurry was prepared by mixing 10 wt% carbon black (60 nm) and 10 wt% carbon black in an aqueous solvent. The carbon black was a mixture of individual particles with a particle size of 38 nm and secondary particles with a particle size of 275 nm, in which primary particles with a particle size of 76 nm were aggregated. The slurry was coated onto a stainless steel foil current collector and then dried to produce a negative electrode comprising a negative electrode coating with a thickness of 12 μm and a current collector with a thickness of 10 μm.

[0128] Comparative Example 1 Using poly(vinylidene fluoride-co-hexafluoropropylene) as the first non-aqueous binder and acrylic binder as the second non-aqueous binder, a binder was prepared in an amount of 0.8 wt% relative to 100 wt% of the positive electrode slurry. The positive electrode active material, solid electrolyte, conductive material, and binder were mixed in an octyl acetate solvent at a weight ratio of approximately 85.35:13.25:0.6:0.8. The positive electrode was manufactured using the same method as in the examples, differing from the above discussion.

[0129] Comparative Example 2 Using poly(vinylidene fluoride-co-hexafluoropropylene) as the first non-aqueous binder and acrylic binder as the second non-aqueous binder, a binder was prepared in an amount of 2 wt% relative to 100 wt% of the positive electrode slurry. The positive electrode active material, solid electrolyte, conductive material, and binder were mixed in an octyl acetate solvent at a weight ratio of approximately 84.31:13.09:0.6:2. The positive electrode was manufactured using the same method as in the examples, differing from the above discussion.

[0130] Comparative Example 3 The positive electrode was manufactured using the same method as in the examples, except that polyvinylidene fluoride (PVdF) was used alone as a binder.

[0131] Comparative Example 4 Polyvinylidene fluoride (PVdF) was used alone as a binder. The binder was prepared in an amount of 1 wt% relative to 100 wt% of the positive electrode slurry. The positive electrode active material, solid electrolyte, conductive material, and binder were mixed in octyl acetate solvent at a weight ratio of approximately 85.17:13.23:0.6:1. The positive electrode was manufactured using the same method as in the examples, differing from the above discussion.

[0132] Evaluation Example 1: Adhesive Force Fix the positive electrode current collector and pull the positive electrode at a 180° angle. Measure the adhesive force according to ASTM D903 standard. The evaluation results of the adhesive force are shown in Table 1 below.

[0133] Table 1:

[0134] Referring to Table 1, it can be observed that the examples exhibit better adhesion than Comparative Examples 1, 3 and 4.

[0135] Evaluation Example 2: Viscosity The viscosity of the positive electrode slurry was determined by measuring the shear viscosity at 20°C using an MCR-302 rheometer purchased from Anton Paar. 10 mL of the positive electrode slurry was injected into the instrument, and then the shear viscosity was measured. The measurement results are listed in Table 2 below.

[0136] Table 2:

[0137] Referring to Table 2 above, it can be observed that the viscosity of the examples is in the range of 1,000 mPa·s to 10,000 mPa·s. Referring to Tables 1 and 2, it can be observed that the adhesive force of Comparative Example 2 is greater than that of the examples because the amount of adhesive in Comparative Example 2 is greater than that in the examples. Therefore, it can be determined that the viscosity of Comparative Example 2 does not fall within the range of 1,000 cps to 10,000 cps.

[0138] Evaluation Example 3: Resistance The DC internal resistance (DCIR) of each of Examples 2 through 4 was measured at 45°C and 50% SOC. The measurement results are listed in Table 3 below.

[0139] Table 3:

[0140] Referring to Table 3 above, it can be observed that the DCIR of the embodiment is less than that of Comparative Examples 3 and 4. Referring to Tables 1 and 3, it can be observed that the resistance of the embodiment is less than that of Comparative Example 2. It can be determined that in the case of Comparative Example 2, due to the large amount of adhesive, the adhesive force is increased, but because the large amount of adhesive leads to a decrease in ionic conductivity, the resistance is high.

[0141] Evaluation Example 4: Specific Capacity The specific capacity of each of Examples 1, 2, 3, and 4 was measured. The all-solid-state batteries of Examples 1 and 2 were charged to 4.2V at 0.5C. Subsequently, the all-solid-state batteries were discharged to 3.0V at 0.1C. Table 4 below shows the specific capacities measured using the methods discussed above.

[0142] Table 4:

[0143] Referring to Table 4 above, it can be observed that the specific capacity of the embodiments is greater than that of Comparative Examples 3 and 4. Referring to Tables 1 and 4, it can be observed that the specific capacity of the embodiments is greater than that of Comparative Example 2. It can be determined that in the case of Comparative Example 2, due to the large amount of binder, the adhesive force is increased, but because the large amount of binder leads to a decrease in ionic conductivity, the specific capacity is low.

[0144] Evaluation Example 5: Lifetime Characteristics The first cycle is defined as charging (charging at 0.33C constant current (CC) / constant voltage (CV) to 4.25V, 0.05C cutoff) and discharging (discharging at 0.33C constant current (CC) to 2.50V, cutoff) of each of the all-solid-state batteries according to Examples and Comparative Example 3. Then, the all-solid-state battery is charged (charged at 1.0C CC / CV to 4.25V, 0.05C cutoff) and discharged (discharged at 0.5C CC to 3.0V, cutoff) while monitoring the cycle until the capacity retention reaches 75%. The capacity retention of the Nth cycle is calculated according to Equation 1.

[0145] Mathematical Equation 1: Capacity retention (%) = [Discharge capacity in the nth cycle / Discharge capacity in the 1st cycle] × 100 Two charge / discharge tests were performed on the all-solid-state batteries according to Examples 1 and 2 (Comparative Example 3). The results of the lifetime characteristics are shown in... Figure 10 middle.

[0146] Reference Figure 10 It can be determined that the capacity retention rate of the embodiment is better than that of Comparative Example 3.

[0147] Evaluation Example 6: Lifetime Characteristics Each of the all-solid-state batteries according to Examples and Comparative Example 4 was charged (charged at 0.33C CC / CV to 4.25V, cutoff at 0.05C) and discharged (discharged at 0.33C CC to 2.50V, cutoff) for 400 cycles. Then, the all-solid-state batteries were charged (charged at 1.0C CC / CV to 4.25V, cutoff at 0.05C) and discharged (discharged at 0.5C CC to 3.0V, cutoff) for 400 cycles. Two charge / discharge tests were performed on the all-solid-state batteries according to Examples and Comparative Example 4. The results of the lifetime characteristics are shown in... Figure 11 middle.

[0148] Reference Figure 11 It can be determined that the capacity retention rate of the embodiment is better than that of Comparative Example 4.

[0149] The binder in the positive electrode of an all-solid-state battery according to some example embodiments of this disclosure may include a first non-aqueous binder and a second non-aqueous binder. Since the binder includes both a first and a second non-aqueous binder, the adhesion between the positive electrode current collector and the positive electrode active material layer including the binder can be improved.

[0150] Additionally, a positive electrode may be included to provide an all-solid-state battery with improved stability and electrochemical properties.

[0151] While this disclosure has been described in conjunction with what is now considered to be exemplary embodiments, it will be understood that this disclosure is not limited to the disclosed exemplary embodiments, but is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Therefore, the foregoing embodiments should be understood as examples and not as limiting this disclosure in any way.

Claims

1. A positive electrode for an all-solid-state battery, the positive electrode comprising: Positive electrode current collector; as well as The positive electrode active material layer is located on the positive electrode current collector. The positive electrode active material layer comprises: a sulfide-based solid electrolyte; a binder, including a first non-aqueous binder and a second non-aqueous binder; and the positive electrode active material. Wherein, the first non-aqueous adhesive includes a fluorinated adhesive, and The second non-aqueous adhesive includes acrylate adhesives.

2. The positive electrode according to claim 1, wherein, The binder in the positive electrode active material layer is present in an amount ranging from 1 wt% to 1.5 wt% relative to 100 wt% of the positive electrode active material layer.

3. The positive electrode according to claim 1, wherein, The amount of the first non-aqueous adhesive in the adhesive is equal to or greater than the amount of the second non-aqueous adhesive in the adhesive.

4. The positive electrode according to claim 1, wherein: Relative to 100 wt% of the adhesive, the first non-aqueous adhesive in the adhesive is present in an amount ranging from 50 wt% to 90 wt%, and The second non-aqueous adhesive in the adhesive is present in an amount ranging from 10 wt% to 50 wt% relative to 100 wt% of the adhesive.

5. The positive electrode according to claim 1, wherein, The first non-aqueous adhesive includes at least one of poly(vinylidene fluoride-co-hexafluoropropylene), poly(vinylidene fluoride-co-trifluoroethylene), poly(vinylidene fluoride-co-trifluorochloroethylene), poly(vinylidene fluoride-co-tetrafluoroethylene), and poly(vinylidene fluoride-co-hexafluoropropylene-co-trifluoroethylene).

6. The positive electrode according to claim 1, wherein, The second non-aqueous adhesive includes at least one of polyacrylic acid, polymethyl methacrylate, poly(butyl acrylate), poly(ethyl acrylate), and poly(2-ethylhexyl acrylate).

7. The positive electrode according to claim 1, wherein, The adhesion force between the positive electrode active material layer and the positive electrode current collector is in the range of 0.5 gf / mm to 2.5 gf / mm.

8. The positive electrode according to claim 1, wherein, The sulfide-based solid electrolyte includes silver-germanium sulfide-type compounds, which include Li 7-a M a PS 6-c X c , 0≤a≤2, and 0≤c≤2, Wherein, X includes at least one of F, Br, Cl and I, and M includes at least one of scandium, yttrium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium, mercury, aluminum, gallium, indium, thallium, silicon, germanium, tin, lead, arsenic, antimony, and bismuth.

9. A method for manufacturing a positive electrode for an all-solid-state battery, the method comprising the following steps: Preparation of slurry; as well as The slurry is coated onto the positive electrode current collector to form a positive electrode active material layer. The step of preparing the slurry includes mixing a positive electrode active material, a sulfide solid electrolyte, and a binder in a non-polar solvent. The adhesive includes: First non-aqueous adhesives, including fluorinated adhesives; and The second type of non-aqueous adhesive includes acrylate adhesives.

10. The method according to claim 9, wherein, The binder in the positive electrode active material layer is present in an amount ranging from 1 wt% to 1.5 wt% relative to 100 wt% of the positive electrode active material layer.

11. The method according to claim 9, wherein, The amount of the first non-aqueous adhesive in the adhesive is equal to or greater than the amount of the second non-aqueous adhesive in the adhesive.

12. The method according to claim 9, wherein: Relative to 100 wt% of the adhesive, the first non-aqueous adhesive in the adhesive is present in an amount ranging from 50 wt% to 90 wt%, and The second non-aqueous adhesive in the adhesive is present in an amount ranging from 10 wt% to 50 wt% relative to 100 wt% of the adhesive.

13. The method according to claim 9, wherein, The first non-aqueous adhesive includes at least one of poly(vinylidene fluoride-co-hexafluoropropylene), poly(vinylidene fluoride-co-trifluoroethylene), poly(vinylidene fluoride-co-trifluorochloroethylene), poly(vinylidene fluoride-co-tetrafluoroethylene), and poly(vinylidene fluoride-co-hexafluoropropylene-co-trifluoroethylene).

14. The method according to claim 9, wherein, The nonpolar solvent includes at least one of butyrate, toluene, xylene, anisole, hexane, heptane, dibromomethane, dichloroethane, ethanol, ethylene glycol ether, and combinations thereof.

15. The method according to claim 9, wherein, The slurry has a viscosity in the range of 1,000 mPa·s to 10,000 mPa·s at a temperature of 20°C.

16. The method according to claim 9, wherein, The adhesion force between the positive electrode active material layer and the positive electrode current collector is in the range of 0.5 gf / mm to 2.5 gf / mm.

17. An all-solid-state battery, the all-solid-state battery comprising: The positive electrode layer and the negative electrode layer are opposite to each other; as well as A solid electrolyte layer is located between the positive electrode layer and the negative electrode layer. The positive electrode layer includes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector. The positive electrode active material layer comprises a positive electrode active material, a binder, and a sulfide-based solid electrolyte. The adhesive includes: a first non-aqueous adhesive, including a fluorinated adhesive; and a second non-aqueous adhesive, including an acrylate adhesive.

18. The all-solid-state battery according to claim 17, wherein, The binder in the positive electrode active material layer is present in an amount ranging from 1 wt% to 1.5 wt% relative to 100 wt% of the positive electrode active material layer.

19. The all-solid-state battery according to claim 17, wherein: Relative to 100 wt% of the adhesive, the first non-aqueous adhesive in the adhesive is present in an amount ranging from 50 wt% to 90 wt%, and The second non-aqueous adhesive in the adhesive is present in an amount ranging from 10 wt% to 50 wt% relative to 100 wt% of the adhesive.

20. The all-solid-state battery according to claim 17, wherein, The first non-aqueous adhesive includes at least one of poly(vinylidene fluoride-co-hexafluoropropylene), poly(vinylidene fluoride-co-trifluoroethylene), poly(vinylidene fluoride-co-trifluorochloroethylene), poly(vinylidene fluoride-co-tetrafluoroethylene), and poly(vinylidene fluoride-co-hexafluoropropylene-co-trifluoroethylene).

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